Method for controlling lots dispatches of tool groups

Abstract

The present invention discloses a method for controlling lots' dispatch of tool groups, and all the lots can be transferred to correct places for further processing. The lots are transferred to the storage places of the tool when there is only a single tool for the next process. A decision step is performed for deciding whether the storage places of the next tool group and the next-next tool group overlap when the next process contains a tool group. If there are overlapped storage places, then the lots will be moved to the overlapped storage place having minimum loading. When there is no overlapped storage place, the lots will be dispatched to the storage place having minimum loading among the next tool group. All the lots can be processed with at minimum moving steps, and all the tools perform their processes under balance loading whenever the productions increase or decrease.

What is claimed is:  
     
       1. A method for controlling lots dispatch among storage places, said lots being processed according to a manufacturing sequence of tool groups, each of which include at least one tool for working on said lots, said method comprising the steps of: 
       transferring said lots to a first storage place serving a single tool when said tool group of a subsequent process of said manufacturing sequence contains only said single tool;  
       transferring said lots to a second storage place having minimum loading among overlapped storage places when said tools of said tool groups for said subsequent process and for a process next following said subsequent process share said overlapped storage places; and  
       transferring said lots to a third storage place having minimum loading among candidate storage places for said subsequent process when said tools of said tool groups for said subsequent process and for the process next following said subsequent process share no said candidate storage places.  
     
     
       2. The method according to claim  1 , wherein each said storage place is a document shelf or a socket. 
     
     
       3. The method according to claim  1 , wherein said step of transferring said lots to said second storage place comprises a step of performing said subsequent process and said process next following said subsequent process after said lots have been transferred. 
     
     
       4. The method according to claim  1 , wherein said transferring said lots to said third storage place comprises a step of judging whether a loading of said overlapped storage place is higher than a loading threshold. 
     
     
       5. The method according to claim  4 , wherein said judging step comprises a step of transferring said lots to said third storage place having minimum loading among said candidate storage places. 
     
     
       6. The method according to claim  1 , wherein said step of transferring said lots to said third storage place comprises a step performing said subsequent process after said lots have been transferred.